Shedding light on dark DNA Most textbook definitions of evolution state that it occurs in two stages: mutation followed by natural selection. DNA mutation is a common and continuous process, and occurs completely at random.
The average adult only eats 15 grams of fiber per day. Women need 25 grams of fiber per day, and men need 38 grams per day, according to the Institute of Medicine.
Women who are 50 years old or younger should include 25 grams of fiber per day in their diets, according to MayoClinic.com. Women who are 51 years old or older should eat 21 grams per day of fiber. As with men, women who are on reduced calorie diets may need less fiber and should aim for 10 to 13 grams of fiber for every 1,000 calories they eat.